My 2 cents: (1) Same thing happened to me. I bought a used telephone off of Ebay and just began practicing picking it up and answering it (this may sound weird to some people but my background is theater). I practiced every day making phone calls to fake people until it became automatic. (2) I read the book by Mel Robbins "5 Second Rule" and that book changed my life as a stutterer. I learned to turn my fear/anxiety into excitement. (3) At work, I applied the these techniques and when the phone rang, I would breathe and then speak. (4) If I had a block, I would disclose my stutter to the caller and 99% of the time, it wasn't an issue. Half of the time the caller would tell me that they had a relative that stuttered. (5) Lastly, if you live in the 🇺🇸, they cannot force you to answer the phone (it's called reasonable accommodations). You are covered under the ADA (Americans with Disabilities Act)